组织工程化人形下颌骨髁状突的实验研究

The Experimental Study of Tissue Engineered Mandible Condyle in the Shape of Human

目的 评价采用组织工程技术构建人下颌骨髁状突软骨复合组织的可行性。方法 以可降解生物材料聚羟基乙酸 (polyglycolicacid ,PGA) /聚乳酸 (polylacticacid ,PLA)预制人下颌骨髁状突模型 ,体外培养扩增牛骨膜成骨细胞和牛关节表面软骨。实验分 3组 :第 1组 ,模型内仅注入 1.5 %藻酸钙和 30 %氧化乙丙烯 ;第 2组 ,模型内分别注入成骨细胞和软骨细胞悬液 ,浓度为 5× 10 7/ml;第 3组 ,模型内接种成骨细胞藻酸钙悬液 ,同时在模型关节表面涂敷软骨细胞 PluronicF12 7悬液 ,浓度为 5× 10 7/ml。分别植入裸鼠皮下 ,12周后取材 ,作大体和组织学观察。结果 第 1组无骨和软骨形成 ,模型支架明显缩小 ,形态不规则 ;第 2组仅留残缺不全的组织结构 ,标本体积缩小变形 ;第 3组形态结构与原植入模型支架相同 ,组织学观察有骨和软骨组织结构 ,两者界面连接有序 ,骨组织内有大量新生骨板。结论 以人工合成生物材料预制人下颌骨髁状突支架 ,采用组织工程技术 ,可以在裸鼠体内构建具有骨软骨复合结构的正常形态的人形下颌骨髁状突 。

Objective This study evaluates the feasibility of creating a tissue engineered adult human mandible condyle composite of bone and cartilage. Methods A polymer template formed in the shape of the human mandible condyle using a scaffold composed of polyglycolic acid (PGA) and polylactic acid (PLA) was seeded with osteoblasts isolated from a bovine periosteum suspended in calcium alginate. Chondrocytes isolated from the same calf suspended in 30% pluronic were then “painted” onto the articular surface of the scaffold and implanted into subcutaneous pockets on the dorsa of athymic mice. Animals were divided into three groups: Group I (n=6) received PGA/PLA scaffold saturated with hydrogels not containing cells. Group II (n=6) received scaffolds seeded with both cell types suspended in saline rather than hydrogels. Group III (n=6) received scaffolds seeded with both cell types suspended in hydrogel composites. Constructs were harvested after 12 weeks, and evaluated grossly and microscopically using histologic stains.Results In group I, constructs formed a small mass without evidence of new bone or cartilage. In group II, constructs were small and irregular in shape. Microscopically they contained scattered islands of bone and cartilage. All specimens in group III retained their original condylar shapes and were quite firm in consistency. Microscopic evaluation revealed trabecular bone interfacing with hyaline cartilage on its articulating surface. Conclusion These findings demonstrate that the composites of bone and cartilage can be engineered to serve as mandibular condylar substitutes. The interdigitation of bone and cartilage at their interface is similar to the normal interface of these composite tissues seen in articulating joints. [